Method and device for selecting serving gateway entity

ABSTRACT

Embodiments of the present invention pertain to the communication field and disclose a method and device for selecting a serving gateway entity. The method includes: receiving an access request message of a user equipment UE sent by a base station, where the access request message includes location information of the base station; acquiring, according to the location information of the base station, a signaling plane address list of serving gateway entities SGWs serving the UE; and selecting, according to failure information of paths between the SGWs and neighboring network elements of the SGWs and the acquired signaling plane address list of SGWs serving the UE, an SGW having no failed path to a neighboring network element of the SGW to serve the UE. The device includes: a receiving module, an acquiring module, and a selecting module.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2011/083544, filed on Dec. 6, 2011, which claims priority toChinese Patent Application No. CN 201010623225.4, filed on Dec. 31,2010, and each application is hereby incorporated by reference in itsentirety.

TECHNICAL FIELD

The present invention relates to the communication field, and inparticular, to a method and device for selecting a serving gatewayentity.

BACKGROUND

The third generation mobile communication standardization organizationlaunches an SAE (System Architecture Evolution, system architectureevolution) system to enhance competitive strength of a future network.The SAE system includes network elements such as an eNodeB (enhancedNodeB, enhanced base station), an MME (Mobility Management Entity,mobility management entity), an SGW (Serving Gateway, serving gatewayentity), and a PGW (Packet Network Data Gateway, packet data networkgateway entity). When a UE (User Equipment, user equipment) accesses theSAE system and needs to establish a connection with a network, the MMEselects an SGW and a PGW for the UE, and then the UE establishes aconnection with a network through the eNodeB, and the SGW and PGWselected by the MME for the UE.

Currently, when the UE needs to establish a connection with the network,the MME acquires, according to the TAI (Tracking Arar Identity, trackingarea identity) of the eNodeB selected by the UE, all SGWs capable ofserving the UE, and acquires, according to an APN (Access Point Name,access point name) subscribed by the UE, a PGW capable of serving theUE; and then selects an SGW from all the acquired SGWs for the UE. Thenthe UE establishes a connection with the network through the eNodeBselected by the UE itself, the SGW selected by the MME, and the acquiredPGW.

If a user plane path between the SGW selected by the MME for the UE andthe eNodeB accessed by the UE fails, or a path between the SGW selectedby the MME for the UE and the acquired PGW fails, establishment of theconnection between the UE and the network fails; in this case, the MMEneeds to reselect an SGW for the UE to establish a connection, causingincrease of time consumption of network access for the UE and a waste ofa lot of network resources.

SUMMARY

To reduce time consumption of network access of a UE and save networkresources, embodiments of the present invention provide a method anddevice for selecting a serving gateway entity. The technical solutionsare as follows:

A method for selecting a serving gateway entity includes:

receiving an access request message of a user equipment UE sent by abase station, where the access request message includes locationinformation of the base station;

acquiring, according to the location information of the base station, asignaling plane address list of serving gateway entities SGWs servingthe UE; and

selecting, according to failure information of paths between the SGWsand neighboring network elements of the SGWs and the acquired signalingplane address list of SGWs serving the UE, an SGW having no failed pathto a neighboring network element of the SGW to serve the UE.

A device for selecting a serving gateway entity includes:

a receiving module, configured to receive an access request message of auser equipment UE sent by a base station, where the access requestmessage includes location information of the base station;

an acquiring module, configured to acquire, according to the locationinformation of the base station received by the receiving module, asignaling plane address list of serving gateway entities SGWs servingthe UE; and

a selecting module, configured to select, according to failureinformation of paths between the SGWs and neighboring network elementsof the SGWs and the signaling plane address list of SGWs serving the UEacquired by the acquiring module, an SGW having no failed path to aneighboring network element of the SGW to serve the UE.

In the method and device for selecting a serving gateway entityaccording to the embodiments of the present invention, an SGW having nofailed path to a neighboring network element of the SGW may be selectedfor a UE according to location information of a base station. In thisway, the probability of successful one-time establishment of aconnection for the UE is ensured, time consumption of network access ofthe UE is reduced, and network resources are saved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a network architecture to which an embodiment of the presentinvention is applied;

FIG. 2 is a flowchart of a method for selecting a serving gateway entityaccording to Embodiment 1 of the present invention;

FIG. 3 is a flowchart of a method for selecting a serving gateway entityaccording to Embodiment 2 of the present invention;

FIG. 4 is a flowchart of determining a failure of a path between an SGWand a PGW according to Embodiment 2 of the present invention;

FIG. 5 is a flowchart of a method for selecting a serving gateway entityaccording to Embodiment 3 of the present invention;

FIG. 6 is a flowchart of a method for selecting a serving gateway entityaccording to Embodiment 4 of the present invention;

FIG. 7 is a flowchart of a method for selecting a serving gateway entityaccording to Embodiment 5 of the present invention; and

FIG. 8 is a schematic diagram of a device for selecting a servinggateway entity according to Embodiment 6 of the present invention.

DESCRIPTION OF EMBODIMENTS

To make the objectives, technical solutions, and advantages of thepresent invention more comprehensible, embodiments of the presentinvention are hereinafter described in detail with reference to theaccompanying drawings.

Embodiments of the present invention are applied to a networkarchitecture shown in FIG. 1. An MME and an eNodeB are connected throughan S1-MME interface, the MME and an SGW are connected through an S11interface, the eNodeB and the SGW are connected through an S1-Uinterface, and the SGW and a PGW are connected through an S5/S8interface. A control plane between the eNodeB and the SGW is deployed onthe MME. Therefore, the path between the MME and the eNodeB and the pathbetween the MME and the SGW are signaling plane paths, the path betweenthe eNodeB and the SGW is a user plane path, and the paths between theSGW and the PGW include a user plane path and a control plane path.

Embodiment 1

As shown in FIG. 2, the embodiment of the present invention provides amethod for selecting a serving gateway entity, where the methodincludes:

Step 101: Receive an access request message of a UE sent by a basestation, where the access request message includes location informationof the base station.

The access request message of the UE may be an initial UE message(Initial UE Message), an S1-AP message, a handover required message, aservice request message, or the like.

Step 102: Acquire, according to the location information of the basestation, a signaling plane address list of SGWs serving the UE.

Step 103: Select, according to failure information of paths between theSGWs and neighboring network elements of the SGWs and the acquiredsignaling plane address list of SGWs serving the UE, an SGW having nofailed path to a neighboring network element of the SGW to serve the UE.

The executor of the method may be an MME, or may be an SGSN (SERVICINGGPRS SUPPORT NODE, GPRS (General Packet Radio Service, general packetradio service) support node), or the like.

In the embodiment of the present invention, the failure information ofthe paths between the SGWs and the neighboring network elements of theSGWs includes:

failure information of paths between the SGWs and the base station,and/or

failure information of paths between the SGWs and PGWs.

Further, the path failure information includes information about whethera path fails, and the path failure information may also include userplane path information and/or signaling plane path information.

Selecting, according to failure information of paths between the SGWsand neighboring network elements of the SGWs and the acquired signalingplane address list of SGWs serving the UE, an SGW having no failed pathto a neighboring network element of the SGW to serve the UE, includes:

determining, according to the failure information of paths between theSGWs and neighboring network elements of the SGWs, a signaling planeaddress of an SGW having a failed path to a neighboring network elementof the SGW, in the signaling plane address list of SGWs; and

removing the signaling plane address of the SGW having a failed path tothe neighboring network element of the SGW, from the signaling planeaddress list of SGWs, and then selecting an SGW for the UE according tothe signaling plane address list of SGWs.

In another embodiment of the present invention, determining, accordingto the failure information of paths between the SGWs and neighboringnetwork elements of the SGWs, a signaling plane address of an SGW havinga failed path to a neighboring network element of the SGW, in thesignaling plane address list of SGWs, includes at least one of thefollowing manners:

determining, according to the location information of the base stationand failure information of user plane paths between the base station andSGWs, a signaling plane address of an SGW having a failed user planepath to the base station;

determining, according to a signaling plane address of an acquired PGWand failure information of signaling plane paths between SGWs and PGWs,a signaling plane address of an SGW having a failed signaling plane pathto the acquired PGW;

determining, according to a user plane address of an acquired PGW andfailure information of user plane paths between SGWs and PGWs, asignaling plane address of an SGW having a failed user plane path to theacquired PGW.

In another embodiment of the present invention, selecting, according tofailure information of paths between the SGWs and neighboring networkelements of the SGWs and the acquired signaling plane address list ofSGWs serving the UE, an SGW having no failed path to a neighboringnetwork element of the SGW to serve the UE, includes:

receiving an S1-AP message sent by the base station after the basestation detects that a user plane path to the selected SGW fails, wherethe S1-AP message includes a failure identifier of the user plane path;and storing correspondence between information of the base station and asignaling plane address of the selected SGW into the failure informationof the user plane paths between the base station and the SGWs; and

selecting, according to the failure information of the user plane pathsbetween the base station and SGWs and the acquired signaling planeaddress list of SGWs serving the UE, an SGW having no failed path to thebase station to serve the UE;

or

receiving an S11 interface message sent by the selected SGW after theselected SGW detects that a user plane path to the base station fails,where the S11 interface message includes a failure identifier of theuser plane path to the base station; and storing correspondence betweeninformation of the base station and a signaling plane address of theselected SGW into the failure information of the user plane pathsbetween the base station and the SGWs; and

selecting, according to the failure information of the user plane pathsbetween the base station and the SGWs and the acquired signaling planeaddress list of SGWs serving the UE, an SGW having no failed path to thebase station to serve the UE;

or

receiving an S11 interface message sent by the selected SGW after theselected

SGW detects that a signaling plane path to an acquired PGW fails, wherethe S11 interface message includes a failure identifier of the signalingplane path to the PGW; and storing correspondence between a signalingplane address of the selected SGW and a signaling plane address of theacquired PGW into the failure information of the signaling plane pathsbetween the SGWs and the PGWs; and

selecting, according to the failure information of the signaling planepaths between the SGWs and the PGWs and the acquired signaling planeaddress list of SGWs serving the UE, an SGW having no failed path to theacquired PGW to serve the UE;

or

receiving an S11 interface message sent by the selected SGW after theselected SGW detects that a user plane path to an acquired PGW fails,where the S11 interface message includes a failure identifier of theuser plane path to the PGW; and storing correspondence between asignaling plane address of the selected SGW and a user plane address ofthe acquired PGW into the failure information of the user plane pathsbetween the SGWs and the PGWs; and

selecting, according to the failure information of the user plane pathsbetween the SGWs and the PGWs and the acquired signaling plane addresslist of SGWs serving the UE, an SGW having no failed path to theacquired PGW to serve the UE.

It should be noted that the base station may be an eNodeB, a NodeB, aradio network controller (RNC), or the like. The location information ofthe base station may include a TAI or CGI (Cell Global Identification,global cell identification) of the base station, or may be geographicallocation information of the base station, such as XX degrees eastlongitude, and XX degrees north latitude. A neighboring network elementmay be a base station, a PGW, or the like.

An SGW having no failed path to a neighboring network element of the SGWis selected to serve the UE, that is, the UE may establish a connectionwith a network side through the selected SGW.

In the embodiment of the present invention, the signaling plane addresslist of SGWs may be acquired according to the location information ofthe base station, and then an SGW having a normal path to a neighboringnetwork element of the SGW is selected for the UE according to thesignaling plane address list of SGWs and the failure information of thepaths between the SGWs and the neighboring network elements of the SGWs,so that the probability of the failure of the path between the selectedSGW and the PGW and the probability of the failure of the user planepath between the selected SGW and the base station are reduced. In thisway, the probability of successful one-time establishment of aconnection for the UE is ensured, time consumption of network access ofthe UE is reduced, and network resources are saved.

Embodiment 2

The embodiment of the present invention provides a method for selectinga serving gateway entity. As shown in FIG. 3, the method includes:

Step 201: A UE sends an attach request (Attach Request) to an eNodeB,where the attach request includes an identifier of the UE.

Before sending the attach request, the UE first encapsulates the attachrequest in the form of a NAS (Non Access Stratum, non access stratum)message and then sends the message to the eNodeB.

The identifier of the UE may be an international mobile subscriberidentification number (International Mobile Subscriber IdentificationNumber, IMSI), an international mobile equipment identity IMEI(International Mobile Equipment Identity, IMEI), or the like.

Step 202: The eNodeB receives the attach request and sends an initial UEmessage (Initial UE Message) to an MME, where the initial UE messageincludes the attach request and location information of the eNodeB.

Each eNodeB in an SAE system selects beforehand, according to the loadof the MMEs, an MME having a normal signaling plane path to the eNodeB.In addition, the location information of the eNodeB may be the TAI orCGI (Cell Global Identification, global cell identification) of theeNodeB.

Step 203: The MME receives the initial UE message, acquires a signalingplane address list of SGWs according to the location information of theeNodeB included in the initial UE message, and acquires a signalingplane address of a PGW according to the identifier of the UE.

Specifically, the MME constructs, according to the location informationof the eNodeB, such as TAI, domain name information corresponding to thelocation information of the eNodeB, acquires, according to theconstructed domain name information, signaling plane addresses of allSGWs corresponding to the constructed domain name information from a DNSServer (Domain Name System Server, domain name system server), and formsa signaling plane address list of SGWs; acquires a corresponding APNfrom an HSS (Home Subscriber server, home subscriber server) accordingto the identifier of the UE, acquires signaling plane addresses of allcorresponding PGWs from the DNS Server according to the acquired APN,and selects a signaling plane address of a PGW for the UE from theacquired signaling plane addresses of all PGWs.

The operation of acquiring, by the MME according to the constructeddomain name information, signaling plane addresses of all SGWscorresponding to the constructed domain name information from a DNSServer, is specifically as follows:

The MME sends a DNS resolve request (DNS Resolve Request) to the DNSServer, where the DNS resolve request includes the constructed domainname information; the DNS Server receives the DNS resolve request,acquires domain names of all corresponding SGWs according to the domainname information included in the DNS resolve request, resolves anacquired domain name of each SGW to acquire a signaling plane address ofeach SGW and form a signaling plane address list of SGWs, and sends aDNS resolve response (DNS Resolve Answer), where the DNS resolveresponse includes the signaling plane address list of SGWs. The MMEreceives the DNS resolve response.

The structure of the TAI is shown in Table 1. The TAI includes an MCC(Mobile Country Code, mobile country code), an MNC (Mobile Network Code,mobile network code), and a TAC (Tracking Area Code, tracking areacode). The MCC and MNC occupy three bytes, and the TAC occupies twobytes.

TABLE 1 Bits Bytes 8 7 6 5 4 3 2 1 d MCC digit 2 MCC digit 1 d + 1 MNCdigit 3 MCC digit 3 d + 2 MNC digit 2 MNC digit 1 d + 3 to d + 4Tracking Area Code (TAC)

The format of the domain name is:

-   -   tac-lb<TAC-low-byte>.tac-hb<TAC-high-byte>.tac.epc.mnc<MNC>.mcc<MCC>.3gppnetwork.org.

It is assumed that: the MCC is 311, the MNC is 990, and the lower byteand higher byte of the TAC are 11 and 40, respectively. Then, theconstructed domain name information is:

-   -   tac-lb11.tac-hb40.tac.epc.mnc990.mcc311.3gppnetwork.org.

Step 204: The MME selects an SGW for the UE according to the signalingplane address list of SGWs, the stored failure information of user planepaths between the eNodeB and SGWs and/or failure information ofsignaling plane paths between SGWs and PGWs.

Specifically, selecting, by the MME, an SGW for the UE according to thesignaling plane address list of SGWs and the stored failure informationof user plane paths between the eNodeB and SGWs, includes:

searching, according to the location information of the eNodeB includedin the initial UE message, the failure information of the user planepaths between the eNodeB and the SGWs for a signaling plane address ofan SGW having a failed user plane path to the eNodeB,

where, the failure information of the user plane paths between theeNodeB and the SGWs includes correspondence between the locationinformation of the eNodeB and signaling plane addresses of SGWs; thelocation information of the eNodeB and a signaling plane address of anSGW included in each record in the failure information of the user planepaths between the eNodeB and the SGWs are used to identify a failed userplane path between the eNodeB and the SGW;

removing, by the MME, a signaling plane address of the failed SGW fromthe acquired signaling plane address list of SGWs, and selecting asignaling plane address of an SGW from the signaling plane addresses ofthe remaining SGWs in the signaling plane address list of SGWs.

Selecting, by the MME, an SGW for the UE according to the acquiredsignaling plane address list of SGWs and the stored failure informationof signaling plane paths between SGWs and PGWs, includes:

searching, according to a signaling plane address of an acquired PGW,the failure information of the signaling plane paths between the SGWsand the PGWs for a signaling plane address of an SGW having a failedsignaling plane path to the PGW corresponding to the signaling planeaddress of the acquired PGW,

where, the failure information of the paths between the SGWs and thePGWs includes correspondence between the signaling plane addresses ofthe SGWs and the signaling plane addresses of the PGWs; a signalingplane address of an SGW and a signaling plane address of a PGW includedin each record in the failure information of the signaling plane pathsbetween the SGWs and the PGWs are used to identify a failed signalingplane path between the SGW and the PGW;

removing, by the MME, a signaling plane address of the failed SGW fromthe acquired signaling plane address list of SGWs, and selects asignaling plane address of an SGW from the signaling plane addresses ofthe remaining SGWs in the signaling plane address list of SGWs.

Selecting, by the MME, an SGW for the UE according to the acquiredsignaling plane address list of SGWs, the stored failure information ofsignaling plane paths between SGWs and PGWs, and stored failureinformation of user plane paths between the eNodeB and SGWs, includes:

searching, according to the location information of the eNodeB includedin the initial UE message, the failure information of the user planepaths between the eNodeB and the SGWs for a signaling plane address ofan SGW having a failed user plane path to the eNodeB;

searching, according to a signaling plane address of an acquired PGW,the failure information of the signaling plane paths between the SGWsand the PGWs for a signaling plane address of an SGW having a failedsignaling plane path to the PGW corresponding to the signaling planeaddress of the acquired PGW; and

removing, by the MME, signaling plane addresses of all failed SGWs fromthe acquired signaling plane address list of SGWs, and selecting asignaling plane address of an SGW from the signaling plane addresses ofthe remaining SGWs in the signaling plane address list of SGWs.

The manner of selecting an SGW may be selecting an SGW nearest to theUE, or selecting an SGW whose load is the lightest, or selecting an SGWrandomly, or the like.

Step 205: The MME sends an S11 interface request message to thecorresponding SGW according to the signaling plane address of theselected SGW, where the S11 interface request message includes thesignaling plane address of an acquired PGW.

The S11 interface request message may be a Create Session Request(create session request).

When the MME selects an SGW for the UE and establishes a connection, theMME stores the signaling plane address of the SGW and the user planeaddress of the SGW, and the MME also stores correspondence between theidentifier of the UE and the SGW serving the UE, that is, the user planeaddress of the SGW serving the UE or the signaling plane address of theSGW may be determined according to the identifier of the UE. Meanwhile,the signaling plane address of the SGW may also be determined accordingto the user plane address of the SGW, and the user plane address of theSGW may also be determined according to the signaling plane address ofthe SGW.

Step 206: The SGW receives the S11 interface request message, anddetermines whether the path between the SGW and the PGW which iscorresponding to the signaling plane address of the PGW included in theS11 interface request message fails.

Specifically, as shown in FIG. 4, the operation of determining, by theSGW, whether the path between the SGW and the PGW which is correspondingto the signaling plane address of the PGW included in the S11 interfacerequest message fails may include the following steps (A) to (E):

(A) The SGW determines the corresponding signaling plane path accordingto the signaling plane address of the PGW included in the S11 interfacerequest message, and forwards the create session request to thecorresponding PGW through the signaling plane path.

The path between the SGW and the PGW includes a signaling plane path anda user plane path; the SGW forwards the create session request to thePGW through the signaling plane path; if the signaling plane pathbetween the SGW and the PGW is normal, the PGW sends a session responsemessage (Create Session Response) to the SGW within a preset duration.

(B) If the PGW receives the create session request, the PGW sends asession response message to the SGW within the preset duration, wherethe session response message includes the user plane address of the PGW.

(C) If the SGW receives, within the preset duration, the sessionresponse message returned by the PGW, the SGW sends an echo probemessage to the PGW according to the user plane path corresponding to theuser plane address included in the session response message; if the SGWdoes not receive, within the preset duration, the session responsemessage returned by the PGW, the SGW determines that the signaling planepath between the SGW and the PGW fails, and this step ends and step 207is executed.

If the SGW receives, within the preset duration, the session responsemessage returned by the PGW, the SGW determines that the signaling planepath between the SGW and the PGW is normal.

(D) If the PGW receives the echo probe message sent by the SGW, the PGWsends an echo response message to the SGW within the preset duration.

(E) If the SGW receives, within the preset duration, the echo responsemessage returned by the PGW, the SGW determines that the user plane pathbetween the SGW and the PGW is normal; if the SGW does not receive,within the preset duration, the echo response message returned by thePGW, the SGW determines that the user plane path to the SGW fails, andstep 207 is executed.

Step 207: The SGW sends an S11 interface message to the MME; if both thesignaling plane path and user plane path between the SGW and the PGW arenormal, the S11 interface message includes an identifier indicating thatthe path to the PGW is normal and includes the user plane addresses ofthe SGW and the PGW.

The S11 interface message may be a Create Session Response.

If the signaling plane path between the SGW and the PGW fails, the S11interface message includes a failure identifier of the signaling planepath to the PGW; if the user plane path between the SGW and the PGWfails, the S11 interface message includes a failure identifier of theuser plane path to the PGW and the user plane address of the PGW.

Step 208: The MME receives the S11 interface message returned by theSGW; if the S11 interface message includes an identifier indicating thatthe path between the SGW and the PGW is normal and the user planeaddresses of the SGW and the PGW, the MME sends an S1-AP responsemessage to the eNodeB, where the S1-AP response message includes theuser plane address of the selected SGW.

The S1-AP response message may be an Initial Context Setup Request.

If the S11 interface message includes a failure identifier of thesignaling plane path between the SGW and the PGW, the MME storescorrespondence between the signaling plane address of the SGW and thesignaling plane address of the PGW into the failure information of thesignaling plane paths between the SGWs and the PGWs, then selects asignaling plane address of an SGW for the UE from the signaling planeaddresses of the remaining unselected SGWs, and returns to step 205.

If the S11 interface message includes a failure identifier of the userplane path between the SGW and the PGW and the user plane addresses ofthe SGW and the PGW, the MME searches, according to the user planeaddress of the SGW, for the signaling plane address of the SGW, storescorrespondence between the signaling plane address of the SGW and theuser plane address of the PGW into the failure information of the userplane paths between the SGWs and the PGWs, and selects a signaling planeaddress of an SGW for the UE from the signaling plane addresses of theremaining unselected SGWs, and returns to step 205.

Step 209: The eNodeB receives the S1-AP response message, anddetermines, according to the user plane address of the SGW included inthe S1-AP response message, whether the user plane path between theeNodeB and the corresponding SGW fails.

Specifically, the eNodeB receives the S1-AP response message, and sendsan echo probe message to the corresponding SGW according to the userplane address of the SGW included in the S1-AP response message; and ifthe eNodeB does not receive, within a preset duration, an echo responsemessage returned by the SGW, the eNodeB determines that the user pathbetween the eNodeB and the SGW fails; otherwise, determines that theuser plane path between the eNodeB and the SGW is normal.

Step 210: If the eNodeB determines that the user plane path between theeNodeB and the SGW is normal, the eNodeB sends an S1-AP message tonotify the MME, where the S1-AP message includes an identifierindicating that the user plane path between the eNodeB and the SGW isnormal.

If the eNodeB determines that the user plane path between the eNodeB andthe SGW fails, the eNodeB sends an S1-AP message to notify the MME,where the S1-AP message includes a failure identifier of the user planepath between the eNodeB and the SGW.

Correspondingly, after receiving the S1-AP message, the MME storescorrespondence between the location information of the eNodeB and thesignaling plane address of the SGW into the failure information of theuser plane paths between the eNodeB and the SGWs, selects a signalingplane address of an SGW for the UE from the signaling plane addresses ofthe remaining unselected SGWs, and returns to step 205.

In the above step, the S1-AP message received by the MME includes anidentifier of the UE. The MME may determine, according to the identifierof the user equipment, the SGW selected for the UE, and therefore, thesignaling plane address of the SGW may be found.

After the UE selects the SGW and acquires the PGW through the MME, theUE may establish a connection with a network, and then use theestablished connection to perform communication.

In the embodiment of the present invention, the MME acquires, accordingto the location information of the eNodeB, signaling plane addresses ofall corresponding SGWs, searches, according to the failure informationof the user plane paths between the eNodeB and the SGWs, for a signalingplane address of an SGW having a failed user plane path to the eNodeB,searches, according to the failure information of the signaling planepaths between the SGWs and the PGWs, for a signaling plane address of anSGW having a failed signaling plane path to an acquired PGW, removes thefound signaling plane addresses of the SGWs from the acquired signalingplane address list of SGWs, and selects a signaling plane address of anSGW for the UE from the signaling plane addresses of the remaining SGWs,so that the probability of the failure of the path between the selectedSGW and the PGW and the probability of the failure of the user planepath between the selected SGW and the eNodeB are reduced. In this way,the probability of successful one-time establishment of a connection forthe UE is ensured, time consumption of network access of the UE isreduced, and network resources are saved.

Embodiment 3

The embodiment of the present invention provides a method for selectinga serving gateway entity. A UE first uses the method of Embodiment 1 toselect an SGW, and then establishes a connection with a network andperforms communication. In a communication process, the UE is handedover between tracking areas, that is, the UE is handed over from an oldtracking area to a new tracking area, and the UE is handed over from anold eNodeB to a New eNodeB and is handed over from an old MME to a NewMME. In this case, the New MME needs to reselect an SGW for the UE.Referring to FIG. 5, the method includes:

Step 301: A UE sends a tracking area update request to a New eNodeB.

The tracking area update request may be a TAU Request (Tracking AreaUpdate request, tracking area update request).

Step 302: The New eNodeB receives the tracking area update request, andsends an S1-AP message to a New MME, where the S1-AP message includesthe tracking area update request and location information of the NeweNodeB.

If the UE is an ECM-IDLE (EPSConnectivityManagement-IDLE, EPS (EvolvedPacket System, evolved packet system) connectivity management-idle)user, the S1-AP message used by the eNodeB is an Initial UE Message; ifthe UE is an ECM-CONNECT (EPSConnectivityManagement-CONNECT, EPSconnectivity management-connected) user, the S1-AP message used by theeNodeB is Uplink NAS Transport.

Step 303: The New MME receives the S1-AP message, and sends a contextrequest to an old mobility management entity.

The context request may be Context Request.

The old mobility management entity is a mobility management entity in anold tracking area, including an MME, an S4 SGSN, or a GnGp SGSN.

Step 304: The old mobility management entity receives the contextrequest, and sends a context response message to the New MME, where thecontext response message includes a signaling plane address and userplane address of a PWG selected by the old MME.

The context response message may be Context Response.

Step 305: The New MME receives the context response message, andacquires a signaling plane address list of SGWs according to thelocation information of the New eNodeB in the S1-AP message.

Specifically, the specific process of acquiring the signaling planeaddress list of SGWs by the New MME is the same as the process ofacquiring the signaling plane address list of SGWs by the MME in step203 of Embodiment 2, and is not further described herein.

Step 306: The New MME selects a New SGW for the UE according to thesignaling plane address list of SGWs, the stored failure information ofuser plane paths between the eNodeB and the SGWs, and failureinformation of signaling plane paths between the SGWs and PGWs and/orfailure information of user plane paths between the SGWs and the PGWs.

Specifically, selecting, by the New MME, a New SGW for the UE accordingto the signaling plane address list of SGWs and the stored failureinformation of user plane paths between the eNodeB and the SGWs,includes:

searching, according to the location information of the New eNodeB, thefailure information of the user plane paths between the eNodeB and theSGWs for a signaling plane address of an SGW having a failed user planepath to the New eNodeB; and

removing the signaling plane address of the failed SGW from the acquiredsignaling plane address list of SGWs, and selecting a signaling planeaddress of a New SGW from the signaling plane addresses of the remainingSGWs in the signaling plane address list of SGWs.

Selecting, by the New MME, a New SGW for the UE according to thesignaling plane address list of SGWs and the stored failure informationof signaling plane paths between the SGWs and the PGWs, includes:

searching, according to the signaling plane address of a PGW included ina context request message, the failure information of the signalingplane paths between the SGWs and the PGWs for a signaling plane addressof an SGW having a failed signaling plane path to the corresponding PGW;and

removing the signaling plane address of the failed SGW from the acquiredsignaling plane address list of SGWs, and selecting a signaling planeaddress of a New SGW from the signaling plane addresses of the remainingSGWs in the signaling plane address list of SGWs.

Selecting, by the New MME, a New SGW for the UE according to thesignaling plane address list of SGWs and the stored failure informationof signaling plane paths between the SGWs and the PGWs, includes:

searching, according to the user plane address of a PGW included in thecontext request message, the failure information of the signaling planepaths between the SGWs and the PGWs for a signaling plane address of anSGW having a failed user plane path to the corresponding PGW; and

removing the signaling plane address of the failed SGW from the acquiredsignaling plane address list of SGWs, and selecting a signaling planeaddress of a New SGW from the signaling plane addresses of the remainingSGWs in the signaling plane address list of SGWs.

Step 307: The New MME sends an S11 interface request message to thecorresponding New SGW according to the signaling plane address of theselected New SGW, where the S11 interface request message includes thesignaling plane address of the PGW included in the context responsemessage.

Step 308: The New SGW receives the S11 interface request message, anddetermines whether the path between the New SGW and the PGW which iscorresponding to the signaling plane address of the PGW included in theS11 interface request message fails.

Specifically, the process of determining, by the New SGW, whether thepath between the New SGW and the PGW fails is the same as the process ofdetermining, by the SGW, whether the path between the SGW and the PGWfails in step 206 of Embodiment 2, and is not further described herein.

Step 309: The New SGW sends an S11 interface message to the New MME; ifthe path between the New SGW and the PGW is normal, the S11 interfacemessage includes an identifier indicating that the path to the PGW isnormal and the user plane address of the New SGW.

If the signaling plane path between the New SGW and the PGW fails, theS11 interface message includes a failure identifier of the signalingplane path between the New SGW and the PGW; if the user plane pathbetween the New SGW and the PGW fails, the S11 interface messageincludes a failure identifier of the user plane path between the New SGWand the PGW.

Step 310: The New MME receives the S11 interface message returned by theNew SGW; if the S11 interface message includes an identifier indicatingthat the path is normal, the New MME sends an S1-AP response message tothe eNodeB, where the S1-AP response message includes the user planeaddress of the New SGW.

If the S11 interface message includes a failure identifier of thesignaling plane path between the New SGW and the PGW, the New MME storescorrespondence between the signaling plane address of the New SGW andthe signaling plane address of the PGW into the failure information ofthe signaling paths between the SGWs and the PGWs, then reselects asignaling plane address of a New SGW for the UE from the signaling planeaddresses of the remaining unselected SGWs, and returns to step 307.

If the S11 interface message includes a failure identifier of the userplane path between the New SGW and the PGW, the New MME storescorrespondence between the signaling plane address of the New SGW andthe user plane address of the PGW into the failure information of theuser plane paths between the SGWs and the PGWs, then reselects asignaling plane address of a New SGW for the UE from the signaling planeaddresses of the remaining unselected SGWs, and returns to step 307.

Step 311: The New eNodeB receives the S1-AP response message, anddetermines, according to the user plane address of the New SGW includedin the S1-AP response message, whether the user plane path between theNew eNodeB and the New SGW fails.

Specifically, the process of determining, by the New eNodeB, whether theuser plane path between the New eNodeB and the New SGW fails is the sameas the process of determining, by the eNodeB, whether the user planepath between the eNodeB and the SGW fails in step 209 of Embodiment 2,and is not further described herein.

Step 312: If the New eNodeB determines that the user plane path betweenthe New eNodeB and the New SGW is normal, the New eNodeB sends an S1-APmessage to notify the New MME, where the S1-AP message includes anidentifier indicating that the user plane path between the New eNodeBand the New SGW is normal.

If the New eNodeB determines that the user plane path between the NeweNodeB and the New SGW fails, the New eNodeB sends an S1-AP message tonotify the New MME, where the S1-AP message includes a failureidentifier of the user plane path between the New eNodeB and the NewSGW.

Correspondingly, the New MME receives the S1-AP message, storescorrespondence between the location information of the New eNodeB andthe ID of the selected New SGW into the failure information of the userplane paths between the eNodeB and the SGWs, then reselects a signalingplane address of a New SGW for the UE from the signaling plane addressesof the remaining unselected SGWs, and returns to step 307.

After the New SGW is selected for the UE, the UE may establish aconnection with the network, and then use the established connection toperform communication.

In the embodiment of the present invention, the New MME acquires thesignaling plane address list of SGWs according to location informationof the New eNodeB, then finds, according to the failure information ofthe user plane paths between the eNodeB and the SGWs, the ID of an SGWhaving a failed user plane path to the New eNodeB, finds, according tothe failure information of the signaling plane paths between the SGWsand the PGWs, a signaling plane address of an SGW having a failedsignaling plane path to an acquired PGW, finds, according to the failureinformation of the user plane paths between the SGWs and the PGWs, auser plane address of an SGW having a failed user plane path to theacquired PGW, removes the found signaling plane addresses of the SGWsfrom the acquired signaling plane address list of SGWs, and selects asignaling plane address of a New SGW for the UE from the signaling planeaddresses of the remaining SGWs, so that the probability of the failureof the path between the selected New SGW and the PGW and the probabilityof the failure of the user plane path between the selected New SGW andthe New eNodeB are reduced. In this way, the probability of successfulone-time establishment of a connection for the UE is ensured, timeconsumption of network access of the UE is reduced, and networkresources are saved.

Embodiment 4

The embodiment of the present invention provides a method for selectinga serving gateway entity. A UE first uses the method of Embodiment 1 toselect an SGW, and then establishes a connection with a network andperforms communication. In a communication process, the UE is handedover between service areas, that is, the UE is handed over from an oldservice area to a new service area, and the UE is handed over from anold eNodeB of the old service area to a New Target eNodeB of the newservice area, and is handed over from an old MME of the old service areato a New Target MME of the new service area. In this case, the UE needsto reselect a new Target SGW. Referring to FIG. 6, the method includes:

Step 401: A UE sends a handover initiation message (Handover Initiation)to an old access side entity, where the handover initiation messageincludes location information of a Target eNodeB.

When the UE is handed over between service areas, the UE accesses a newTarget eNodeB in a new service area and acquires location information ofthe Target eNodeB.

The old access side entity is an access side entity in an old servicearea, including: an eNodeB, an RNC (Radio Network Controller, radionetwork controller), or a BSS (Base Station Sub-system, base stationsub-system).

Step 402: The old access side entity receives the handover initiationmessage, and sends a handover required message to an old mobilitymanagement entity, where the handover required message includes locationinformation of the Target eNodeB included in the handover initiationmessage.

The old mobility management entity is a mobility management entity inthe old service area, including an MME, an S4 SGSN, or a GnGp SGSN.

Step 403: The old mobility management entity receives the handoverrequired message, and sends a forward relocation request (ForwardRelocation Request) to a Target MME, where the forward relocationrequest includes location information of the Target eNodeB and thesignaling plane address and user plane address of a PGW acquired by anold MME.

Step 404: The Target MME receives the forward relocation request, andacquires a signaling plane address list of SGWs according to thelocation information of the Target eNodeB included in the forwardrelocation request.

Specifically, the process of acquiring the signaling plane address listof SGWs by the Target MME according to location information of theTarget eNodeB is the same as the process of acquiring the signalingplane address list of SGWs by the eNodeB in step 203 of Embodiment 2,and is not further described herein.

Step 405: The Target MME selects a signaling plane address of a TargetSGW for the UE according to the signaling plane address list of SGWs,the stored failure information of the user plane paths between theeNodeB and the SGWs, and failure information of the signaling planepaths between the SGWs and PGWs and/or failure information of the userplane paths between the SGWs and the PGWs.

Specifically, selecting, by the Target MME, a Target SGW for the UEaccording to the signaling plane address list of SGWs and the storedfailure information of the user plane paths between the eNodeB and theSGWs, includes:

searching, according to the location information of the Target eNodeB,the failure information of the user plane paths between the eNodeB andthe SGWs for a signaling plane address of an SGW having a failed userplane path to the Target eNodeB; and

removing the signaling plane address of the failed SGW from the acquiredsignaling plane address list of SGWs, and selecting a signaling planeaddress of a Target SGW from the signaling plane addresses of theremaining SGWs in the signaling plane address list of SGWs.

Selecting, by the Target MME, a Target SGW for the UE according to thesignaling plane address list of SGWs and the stored failure informationof the signaling plane paths between the SGWs and the PGWs, includes:

searching, according to the signaling plane address of the PGW includedin the forward relocation request, the failure information of thesignaling plane paths between the SGWs and the PGWs for a signalingplane address of an SGW having a failed signaling plane path to thecorresponding PGW; and

removing the signaling plane address of the failed SGW from the acquiredsignaling plane address list of SGWs, and selecting a signaling planeaddress of a Target SGW from the signaling plane addresses of theremaining SGWs in the signaling plane address list of SGWs.

Selecting, by the Target MME, a Target SGW for the UE according to thesignaling plane address list of SGWs and the stored failure informationof the user plane paths between the SGWs and the PGWs, includes:

searching, according to the signaling plane address of the PGW includedin the forward relocation request, the failure information of the userplane paths between the SGWs and the PGWs for a signaling plane addressof an SGW having a failed user plane path to the corresponding PGW; and

removing the signaling plane address of the failed SGW from the acquiredsignaling plane address list of SGWs, and selecting a signaling planeaddress of a Target SGW from the signaling plane addresses of theremaining SGWs in the signaling plane address list of SGWs.

Step 406: The Target MME sends an S11 interface request message to thecorresponding Target SGW according to the signaling plane address of theselected Target SGW, where the S11 interface request message includesthe signaling plane address of the PGW included in the forwardrelocation request.

Step 407: The Target SGW receives the S11 interface request message, anddetermines whether the path between the Target SGW and the PGW which iscorresponding to the signaling plane address of the PGW included in theS11 interface request message fails.

Specifically, the process of determining, by the Target SGW, whether thepath between the Target SGW and the PGW fails is the same as the processof determining, by the SGW, whether the path between the SGW and the PGWfails in step 206 of Embodiment 2, and is not further described herein.

Step 408: The Target SGW sends an S11 interface message to the TargetMME; if both the user plane path and signaling plane path between theTarget SGW and the PGW are normal, the S11 interface message includes anidentifier of the path between the Target SGW and the PGW is normal andthe user plane address of the Target SGW.

If the signaling plane path between the Target SGW and the PGW fails,the S11 interface message includes a failure identifier of the signalingplane path between the Target SGW and the PGW; if the user plane pathbetween the Target SGW and the PGW fails, the S11 interface messageincludes a failure identifier of the user plane path between the TargetSGW and the PGW.

Step 409: The Target MME receives the S11 interface message returned bythe Target SGW; if the S11 interface message includes an identifierindicating that the path between the SGW and the PGW is normal, theTarget MME sends an S1-AP response message to the Target eNodeB, wherethe S1-AP response message includes the user plane address of the TargetSGW.

If the S11 interface message includes a failure identifier of asignaling plane path between an SGW and a PGW, the Target MME storescorrespondence between the signaling plane address of the Target SGW andthe signaling plane address of the PGW into the failure information ofthe signaling plane paths between the SGWs and the PGWs, then reselectsa signaling plane address of an SGW for the UE from the signaling planeaddresses of the remaining unselected SGWs, and returns to step 406.

If the S11 interface message includes a failure identifier of a userplane path between an SGW and a PGW, the Target MME storescorrespondence between the signaling plane address of the Target SGW andthe user plane address of the PGW into the failure information of theuser plane paths between the SGWs and the PGWs, reselects a signalingplane address of an SGW for the UE from the signaling plane addresses ofthe remaining unselected SGWs, and then returns to step 406.

Step 410: The Target eNodeB receives the S1-AP response message, anddetermines, according to the user plane address of the Target SGWincluded in the S1-AP response message, whether the user plane pathbetween the Target eNodeB and the Target SGW fails.

Specifically, the process of determining, by the Target eNodeB, whetherthe user plane path between the Target eNodeB and the Target SGW failsis the same as the process of determining, by the eNodeB, whether theuser plane path between the eNodeB and the SGW fails in step 209 ofEmbodiment 2, and is not further described herein.

Step 411: If the Target eNodeB determines that the user plane pathbetween the Target eNodeB and the Target SGW is normal, the TargeteNodeB sends an S1-AP message to notify the Target MME, where the S1-APmessage includes an identifier indicating that the user plane pathbetween the Target eNodeB and the Target SGW is normal.

If the Target eNodeB determines that the user plane path between theTarget eNodeB and the Target SGW fails, the Target eNodeB sends an S1-APmessage to notify the Target MME, where the S1-AP message includes afailure identifier of the user plane path between the Target eNodeB andthe Target SGW.

Correspondingly, the Target MME receives the S1-AP message, storescorrespondence between the location information of the Target eNodeB andthe signaling plane address of the Target SGW into the failureinformation of the user plane paths between the eNodeB and the SGWs,reselects a signaling plane address of a new Target SGW for the UE fromthe signaling plane addresses of the remaining unselected SGWs, andreturns to step 406.

In the embodiment of the present invention, the Target MME acquires thesignaling plane address list of SGWs according to location informationof the Target eNodeB, then finds, according to the failure informationof the user plane paths between the eNodeB and the SGWs, a signalingplane address of an SGW having a failed user plane path to the TargeteNodeB, finds, according to the failure information of the paths betweenthe SGWs and the PGWs, a signaling plane address of an SGW having afailed signaling plane path to an acquired PGW, finds, according to thefailure information of the user paths between the SGWs and the PGWs, asignaling plane address of an SGW having a failed user plane path to theacquired PGW, removes the found signaling plane addresses of the SGWsfrom the acquired signaling plane address list of SGWs, and selects asignaling plane address of a Target SGW for the UE from the signalingplane addresses of the remaining SGWs, so that the probability of thefailure of the path between the selected Target SGW and the PGW and theprobability of the failure of the user plane path between the selectedTarget SGW and the Target eNodeB are reduced. In this way, theprobability of successful one-time establishment of a connection for theUE is ensured, time consumption of network access of the UE is reduced,and network resources are saved.

Embodiment 5

The embodiment of the present invention provides a method for selectinga serving gateway entity. A UE uses the method of Embodiment 2 to selectan SGW, and then establishes a connection with a network and performscommunication; an eNodeB detects in real time whether a user plane pathbetween the eNodeB and an SGW fails, and if detecting that the userplane path between the eNodeB and the SGW fails, sends an S1-AP messageto notify an MME, where the S1-AP message includes a failure identifier.The MME receives the S1-AP message, and stores correspondence betweenlocation information of the eNodeB and a signaling plane address of theSGW into failure information of user plane paths between the eNodeB andSGWs.

In addition, the SGW also detects in real time whether a user plane pathbetween the SGW and the eNodeB fails, and if so, sends an S11 interfacemessage to the MME, where the S11 interface message includes a failureidentifier of the user plane path to the eNodeB. The MME receives theS11 interface message, and stores correspondence between locationinformation of the eNodeB and a signaling plane address of the SGW intothe failure information of the user plane paths between the eNodeB andthe SGWs.

Further, the SGW detects in real time whether a signaling plane pathbetween the SGW and a PGW fails, and if detecting that the signalingplane path between the SGW and the PGW fails, sends an S11 interfacemessage to the MME, where the S11 interface message includes a failureidentifier of the signaling plane path to the PGW. The MME receives theS11 interface message, and stores correspondence between a signalingplane address of the SGW and a signaling plane address of the PGW intofailure information of signaling plane paths between SGWs and PGWs.

Further, the SGW detects in real time whether a user plane path betweenthe SGW and the PGW fails, and if detecting that the user plane pathbetween the SGW and the PGW fails, sends an S11 interface message to theMME, where the S11 interface message includes a failure identifier ofthe user plane path to the PGW. The MME receives the S11 interfacemessage, and stores correspondence between a user plane address of theSGW and a user plane address of the PGW into failure information of userplane paths between the SGWs and the PGWs.

If the user plane path between the eNodeB and the SGW fails, the SGWdetects that the signaling plane path between the SGW and the PGW fails,the SGW detects that the user plane path between the SGW and the PGWfails, or the SGW detects that a path between the SGW and the PGW fails,the MME needs to reselect a New SGW for the UE. Referring to FIG. 7, themethod includes:

Step 501: A UE sends a service request (Server Request) to an eNodeB.

If a user plane path between an eNodeB and an SGW fails, an SGW detectsthat a signaling plane path between the SGW and a PGW fails, the SGWdetects that a user plane path between the SGW and the PGW fails, or theSGW detects that a user plane path between the SGW and the eNodeB fails,the eNodeB releases the air interface with the UE; and then the UE sendsa service request to request selecting a New SGW.

Step 502: The eNodeB receives the service request, adds locationinformation of the eNodeB to the service request, and forwards theservice request to the MME.

Step 503: The MME receives the service request, and acquires a signalingplane address list of SGWs according to the location information of theeNodeB included in the service request.

Specifically, the process of acquiring the signaling plane address listof SGWs by the MME according to location information of the eNodeB isthe same as the process of acquiring the signaling plane address list ofSGWs by the eNodeB in step 203 of Embodiment 2, and is not furtherdescribed herein.

Step 504: The MME reselects a New SGW for the UE according to theacquired signaling plane address list of SGWs, the failure informationof user plane paths between the eNodeB and SGWs, and failure informationof signaling plane paths between the SGWs and PGWs, and/or failureinformation of user plane paths between the SGWs and the PGWs.

Specifically, selecting, by the MME, a New SGW for the UE according tothe signaling plane address list of SGWs and the stored failureinformation of user plane paths between the eNodeB and SGWs, includes:

searching, according to the location information of the eNodeB, thefailure information of the user plane paths between the eNodeB and theSGWs for a signaling plane address of an SGW having a failed user planepath to the eNodeB; and

removing the signaling plane address of the failed SGW from the acquiredsignaling plane address list of SGWs, and selecting a signaling planeaddress of a New SGW from the signaling plane addresses of the remainingSGWs in the signaling plane address list of SGWs.

Selecting, by the MME, a New SGW for the UE according to the signalingplane address list of SGWs and the stored failure information of userplane paths between the SGWs and PGWs, includes:

searching, according to a signaling plane address of an acquired PGW,the failure information of the signaling plane paths between the SGWsand the PGWs for a signaling plane address of an SGW having a failedsignaling plane path to the PGW; and

removing the signaling plane address of the failed SGW from the acquiredsignaling plane address list of SGWs, and selecting a signaling planeaddress of a New SGW from the signaling plane addresses of the remainingSGWs in the signaling plane address list of SGWs.

Selecting, by the MME, a New SGW for the UE according to the signalingplane address list of SGWs and the stored failure information ofsignaling plane paths between the SGWs and PGWs, includes:

searching, according to a user plane address of an acquired PGW, thefailure information of the user plane paths between the SGWs and thePGWs for a signaling plane address of an SGW having a failed user planepath to the PGW; and

removing the signaling plane address of the failed SGW from the acquiredsignaling plane address list of SGWs, and selecting a signaling planeaddress of a New SGW from the signaling plane addresses of the remainingSGWs in the signaling plane address list of SGWs.

Step 505: The MME sends an S11 interface request message to thecorresponding New SGW according to the signaling plane address of theselected New SGW, where the S11 interface request message includes thesignaling plane address of an acquired PGW.

Step 506: The New SGW receives the S11 interface request message, anddetermines whether a path between the New SGW and the PGW which iscorresponding to the signaling plane address of the PGW included in theS11 interface request message fails.

Specifically, the process of determining, by the New SGW, whether thepath between the New SGW and the PGW fails is the same as the process ofdetermining, by the SGW, whether the path between the SGW and the PGWfails in step 206 of Embodiment 2, and is not further described herein.

Step 507: The New SGW sends an S11 interface message to a New MME; ifthe path between the New SGW and the PGW is normal, the S11 interfacemessage includes an identifier of the path between the New SGW and thePGW is normal and the user plane address of the New SGW.

If the signaling plane path between the New SGW and the PGW fails, theS11 interface message includes a failure identifier of the signalingplane path between the New SGW and the PGW; if the user plane pathbetween the New SGW and the PGW fails, the S11 interface messageincludes a failure identifier of the user plane path between the New SGWand the PGW.

Step 508: The MME receives the S11 interface message returned by the NewSGW; if the S11 interface message includes an identifier indicating thatthe path is normal, the MME sends an S1-AP response message to theeNodeB, where the S1-AP response message includes the user plane addressof the New SGW.

If the S11 interface message includes a failure identifier of thesignaling plane path between the New SGW and the PGW, the MME storescorrespondence between a signaling plane address of the New SGW and asignaling plane address of the PGW into the failure information of thesignaling plane paths between the SGWs and the PGWs, reselects asignaling plane address of a New SGW for the UE from the signaling planeaddresses of the remaining unselected SGWs, and then returns to step505.

If the S11 interface message includes a failure identifier of the userplane path between the New SGW and the PGW, the MME storescorrespondence between a signaling plane address of the New SGW and auser plane address of the PGW into the failure information of the userplane paths between the SGWs and the PGWs, reselects a new signalingplane address of a New SGW for the UE from the signaling plane addressesof the remaining unselected SGWs, and then returns to step 505.

Step 509: The eNodeB receives the S1-AP response message, anddetermines, according to the user plane address of the SGW included inthe S1-AP response message, whether the user plane path between theeNodeB and the corresponding New SGW fails.

Specifically, the process of determining, by the eNodeB, whether thepath between the eNodeB and the New SGW fails is the same as the processof determining, by the eNodeB, whether the path between the eNodeB andthe SGW fails in step 209 of Embodiment 2, and is not further describedherein.

Step 510: If the eNodeB determines that the user plane path between theeNodeB and the New SGW is normal, the eNodeB sends an S1-AP message tonotify the MME, where the S1-AP message includes an identifierindicating that the user plane path between the eNodeB and the SGW isnormal.

If the eNodeB determines that the user plane path between the eNodeB andthe New SGW fails, the eNodeB sends an S1-AP message to notify the MME,where the S1-AP message includes a failure identifier of the user planepath between the eNodeB and the PGW.

Correspondingly, the MME receives the S1-AP message, storescorrespondence between location information of the eNodeB and asignaling plane address of the selected SGW into the failure informationof the user plane paths between the eNodeB and the SGWs, reselects asignaling plane address of a New SGW for the UE from the signaling planeaddresses of the remaining unselected SGWs, and returns to step 505.

After an ID of the New SGW is selected for the UE, the UE may establisha connection with a network, and then use the established connection toperform communication.

In the embodiment of the present invention, the MME acquires signalingplane addresses of all corresponding SGWs according to locationinformation of the eNodeB, then finds, according to the failureinformation of the user plane paths between the eNodeB and the SGWs, asignaling plane address of an SGW having a failed user plane path to theeNodeB, finds, according to the failure information of the paths betweenthe SGWs and the PGWs, a signaling plane address of an SGW having afailed signaling plane path to an acquired PGW, finds, according to thefailure information of the user plane paths between the SGWs and thePGWs, a signaling plane address of an SGW having a failed user planepath to the acquired PGW, removes the found signaling plane addresses ofthe SGWs from the acquired signaling plane addresses of all the SGWs,and selects a signaling plane address of a New SGW for the UE from thesignaling plane addresses of the remaining SGWs, so that the probabilityof the failure of the path between the selected New SGW and the PGW andthe probability of the failure of the user plane path between theselected New SGW and the New eNodeB are reduced. In this way, theprobability of successful one-time establishment of a connection for theUE is ensured, time consumption of network access of the UE is reduced,and network resources are saved.

Embodiment 6

As shown in FIG. 8, the embodiment of the present invention provides adevice for selecting a serving gateway entity, where the deviceincludes:

a receiving module 601, configured to receive an access request messageof a UE sent by a base station, where the access request messageincludes location information of the base station;

an acquiring module 602, configured to acquire, according to thelocation information of the base station received by the receivingmodule 601, a signaling plane address list of SGWs serving the UE; and

a selecting module 603, configured to select, according to failureinformation of paths between the SGWs and neighboring network elementsof the SGWs and the signaling plane address list of SGWs serving the UEacquired by the acquiring module 602, an SGW having no failed path to aneighboring network element of the SGW to serve the UE.

In an embodiment of the present invention, the selecting module 603specifically includes:

an acquiring unit, configured to determine, according to the failureinformation of the paths between the SGWs and the neighboring networkelements of the SGWs, a signaling plane address of each SGW having afailed path to a neighboring network element of the each SGW, in thesignaling plane address list of SGWs; and

a selecting unit, configured to remove the signaling plane address ofthe SGW having a failed path to a neighboring network element of theSGW, from the signaling plane address list of SGWs, and then select anSGW for the UE according to the signaling plane address list of SGWs.

The failure information of paths between the SGWs and the neighboringnetwork elements of the SGWs includes at least one piece of thefollowing information:

failure information of user plane paths between the base station andSGWs;

failure information of signaling plane paths between the SGWs and PGWs;and

failure information of user plane paths between the SGWs and the PGWs.

In another embodiment of the present invention, the acquiring unitincludes at least one of the following acquiring subunits:

a first acquiring subunit, configured to determine, according to thelocation information of the base station and the failure information ofthe user plane paths between the base station and the SGWs, a signalingplane address of an SGW having a failed user plane path to the basestation;

a second acquiring subunit, configured to determine, according to asignaling plane address of an acquired PGW and the failure informationof the signaling plane paths between the SGWs and the PGWs, a signalingplane address of an SGW having a failed signaling plane path to theacquired PGW;

a third acquiring subunit, configured to determine, according to a userplane address of an acquired PGW and the failure information of the userplane paths between the SGWs and the PGWs, a signaling plane address ofan SGW having a failed user plane path to the acquired PGW.

Further, in another embodiment of the present invention, the selectingmodule 603 includes:

a first storing unit, configured to receive an S1-AP message sent by thebase station after the base station detects that a user path to theselected SGW fails, where the S1-AP message includes a failureidentifier of the user plane path; and store correspondence betweenlocation information of the base station and a signaling plane addressof the selected SGW into the failure information of the user plane pathsbetween the base station and the SGWs; and

a first selecting unit, configured to select, according to the failureinformation of the user plane paths between the base station and theSGWs and the acquired signaling plane address list of SGWs serving theUE, an SGW having no failed path to the base station to serve the UE.

Further, in another embodiment of the present invention, the selectingmodule 603 includes:

a second storing unit, configured to receive an S11 interface messagesent by the selected SGW after the selected SGW detects that a user pathto the base station fails, where the S11 interface message includes afailure identifier of the user plane path to the base station; and storecorrespondence between location information of the base station and asignaling plane address of the selected SGW into the failure informationof the user plane paths between the base station and the SGWs; and

a second selecting unit, configured to select, according to the failureinformation of the user plane paths between the base station and theSGWs and the acquired signaling plane address list of SGWs serving theUE, an SGW having no failed path to the base station to serve the UE.

Further, in another embodiment of the present invention, the selectingmodule 603 includes:

a third storing unit, configured to receive an S11 interface messagesent by the selected SGW after the selected SGW detects that a signalingplane path to an acquired PGW fails, where the S11 interface messageincludes a failure identifier of the signaling plane path to the PGW;and store correspondence between a signaling plane address of theselected SGW and a signaling plane address of the acquired PGW into thefailure information of the signaling plane paths between the SGWs andthe PGWs; and

a third selecting unit, configured to select, according to the failureinformation of the signaling plane paths between the SGWs and the PGWsand the acquired signaling plane address list of SGWs serving the UE, anSGW having no failed path to the acquired PGW to serve the UE.

Further, in another embodiment of the present invention, the selectingmodule 603 includes:

a fourth storing unit, configured to receive an S11 interface messagesent by the selected SGW after the selected SGW detects that a userplane path to an acquired PGW fails, where the S11 interface messageincludes a failure identifier of the user plane path to the PGW; andstore correspondence between a signaling plane address of the selectedSGW and a user plane address of the acquired PGW into the failureinformation of the user paths between the SGWs and the PGWs; and

a fourth selecting unit, configured to select, according to the failureinformation of the user plane paths between the SGWs and the PGWs andthe acquired signaling plane address list of SGWs serving the UE, an SGWhaving no failed path to the acquired PGW to serve the UE.

In the embodiment of the present invention, the MME acquires, accordingto the location information of the eNodeB, signaling plane addresses ofall corresponding SGWs, searches, according to the failure informationof the user plane paths between the eNodeB and the SGWs, for a signalingplane address of an SGW having a failed user plane path to the eNodeB,searches, according to the failure information of the signaling planepaths between the SGWs and the PGWs, for a signaling plane address of anSGW having a failed signaling plane path to an acquired PGW, removes thefound signaling plane addresses of the SGWs from the acquired signalingplane address list of SGWs, and selects a signaling plane address of anSGW for the UE from the signaling plane addresses of the remaining SGWs,so that the probability of the failure of the path between the selectedSGW and the PGW and the probability of the failure of the user planepath between the selected SGW and the eNodeB are reduced. In this way,the probability of successful one-time establishment of a connection forthe UE is ensured, time consumption of network access of the UE isreduced, and network resources are saved.

All or a part of the content disclosed in the technical solutionsprovided by the embodiments can be implemented by software programming.The programs may be stored in a readable storage medium, such as a harddisk, a CD-ROM, or a floppy disk in a computer.

The above description is merely about preferred embodiments of thepresent invention, but is not intended to limit the present invention.Any modification, equivalent substitution, improvement, and so on withinthe idea and principle of the present invention shall fall within theprotection scope of the present invention.

What is claimed is:
 1. A method for selecting a serving gateway entity,wherein the method comprises: receiving an access request message of auser equipment (UE) sent by a base station, wherein the access requestmessage comprises location information of the base station; acquiring,according to the location information of the base station, a signalingplane address list of serving gateway entities (SGWs) serving the UE;and selecting, according to failure information of paths between theSGWs and neighboring network elements of the SGWs and the acquiredsignaling plane address list of SGWs serving the UE, an SGW having nofailed path to a neighboring network element of the SGW to serve the UE.2. The method according to claim 1, wherein the selecting, according tofailure information of paths between the SGWs and neighboring networkelements of the SGWs and the acquired signaling plane address list ofSGWs serving the UE, an SGW having no failed path to a neighboringnetwork element of the SGW to serve the UE, comprises: determining,according to the failure information of the paths between the SGWs andthe neighboring network elements of the SGWs, a signaling plane addressof each SGW having a failed path to a neighboring network element of theeach SGW, in the signaling plane address list of SGWs; and removing thesignaling plane address of the each SGW having a failed path to aneighboring network element of the each SGW, from the signaling planeaddress list of SGWs, and then selecting an SGW for the UE according tothe signaling plane address list of SGWs.
 3. The method according toclaim 1, wherein: the failure information of the paths between the SGWsand the neighboring network elements of the SGWs comprises at least onepiece of the following information: failure information of user planepaths between the base station and the SGWs; failure information ofsignaling plane paths between the SGWs and packet data network gatewayentities (PGWs); and failure information of user plane paths between theSGWs and the PGWs.
 4. The method according to claim 3, wherein thedetermining, according to the failure information of the paths betweenthe SGWs and the neighboring network elements of the SGWs, a signalingplane address of each SGW having a failed path to a neighboring networkelement of the SGW, in the signaling plane address list of SGWs,comprises at least one of the following manners: determining, accordingto the location information of the base station and the failureinformation of the user plane paths between the base station and theSGWs, a signaling plane address of the each SGW having a failed userplane path to the base station; determining, according to a signalingplane address of an acquired PGW and the failure information of thesignaling plane paths between the SGWs and the PGWs, a signaling planeaddress of each SGW having a failed signaling plane path to the acquiredPGW; determining, according to a user plane address of an acquired PGWand the failure information of the user plane paths between the SGWs andthe PGWs, a signaling plane address of each SGW having a failed userplane path to the acquired PGW.
 5. The method according to claim 3,wherein the selecting, according to failure information of paths betweenthe SGWs and neighboring network elements of the SGWs and the acquiredsignaling plane address list of SGWs serving the UE, an SGW having nofailed path to a neighboring network element of the SGW to serve the UE,comprises: receiving an S1-AP message sent by the base station after thebase station detects that a user plane path to the selected SGW fails,wherein the S1-AP message comprises a failure identifier of the userplane path; and storing correspondence between information of the basestation and a signaling plane address of the selected SGW into thefailure information of the user plane paths between the base station andthe SGWs; and selecting, according to the failure information of theuser plane paths between the base station and the SGWs and the acquiredsignaling plane address list of SGWs serving the UE, an SGW having nofailed path to the base station to serve the UE.
 6. The method accordingto claim 3, wherein the selecting, according to failure information ofpaths between the SGWs and neighboring network elements of the SGWs andthe acquired signaling plane address list of SGWs serving the UE, an SGWhaving no failed path to a neighboring network element of the SGW toserve the UE, comprises: receiving an S11 interface message sent by theselected SGW after the selected SGW detects that a user plane path tothe base station fails, wherein the S11 interface message comprises afailure identifier of the user plane path to the base station; andstoring correspondence between information of the base station and asignaling plane address of the selected SGW into the failure informationof the user plane paths between the base station and the SGWs; andselecting, according to the failure information of the user plane pathsbetween the base station and the SGWs and the acquired signaling planeaddress list of SGWs serving the UE, an SGW having no failed path to thebase station to serve the UE.
 7. The method according to claim 3,wherein the selecting, according to failure information of paths betweenthe SGWs and neighboring network elements of the SGWs and the acquiredsignaling plane address list of SGWs serving the UE, an SGW having nofailed path to a neighboring network element of the SGW to serve the UE,comprises: receiving an S11 interface message sent by the selected SGWafter the selected SGW detects that a signaling plane path to anacquired PGW fails, wherein the S11 interface message comprises afailure identifier of the signaling plane path to the PGW; and storingcorrespondence between a signaling plane address of the selected SGW anda signaling plane address of the acquired PGW into the failureinformation of the signaling plane paths between the SGWs and the PGWs;and selecting, according to the failure information of the signalingplane paths between the PGWs and the SGWs and the acquired signalingplane address list of SGWs serving the UE, an SGW having no failed pathto the PGW to serve the UE.
 8. The method according to claim 3, whereinthe selecting, according to failure information of paths between theSGWs and neighboring network elements of the SGWs and the acquiredsignaling plane address list of SGWs serving the UE, an SGW having nofailed path to a neighboring network element of the SGW to serve the UE,comprises: receiving an S11 interface message sent by the selected SGWafter the selected SGW detects that a user plane path to an acquired PGWfails, wherein the S11 interface message comprises a failure identifierof the user plane path to the PGW; and storing correspondence between asignaling plane address of the selected SGW and a user plane address ofthe acquired PGW into the failure information of the user plane pathsbetween the SGWs and the PGWs; and selecting, according to the failureinformation of the user plane paths between the PGWs and the SGWs andthe acquired signaling plane address list of SGWs serving the UE, an SGWhaving no failed path to the PGW to serve the UE.
 9. A device forselecting a serving gateway entity, wherein the device comprises: areceiving module, configured to receive an access request message of auser equipment (UE) sent by a base station, wherein the access requestmessage comprises location information of the base station; an acquiringmodule, configured to acquire, according to the location information ofthe base station received by the receiving module, a signaling planeaddress list of serving gateway entities (SGWs) serving the UE; and aselecting module, configured to select, according to failure informationof paths between the SGWs and neighboring network elements of the SGWsand the signaling plane address list of SGWs serving the UE acquired bythe acquiring module, an SGW having no failed path to a neighboringnetwork element of the SGW to serve the UE.
 10. The device according toclaim 9, wherein the selecting module specifically comprises: anacquiring unit, configured to determine, according to the failureinformation of the paths between the SGWs and the neighboring networkelements of the SGWs, a signaling plane address of each SGW having afailed path to a neighboring network element of the each SGW, in thesignaling plane address list of SGWs; and a selecting unit, configuredto remove the signaling plane address of the each SGW having a failedpath to a neighboring network element of the each SGW determined by theacquiring unit, from the signaling plane address list of SGWs, and thenselecting an SGW for the UE according to the signaling plane addresslist of SGWs.
 11. The device according to claim 9, wherein: the failureinformation of the paths between the SGWs and the neighboring networkelements comprises of the SGWs at least one piece of the followinginformation: failure information of user plane paths between the basestation and the SGWs; failure information of signaling plane pathsbetween the SGWs and packet data network gateway entities (PGWs); andfailure information of user plane paths between the SGWs and the PGWs.12. The device according to claim 11, wherein the acquiring unitcomprises at least one of the following acquiring subunits: a firstacquiring subunit, configured to determine, according to the locationinformation of the base station and the failure information of the userplane paths between the base station and the SGWs, a signaling planeaddress of each SGW having a failed user plane path to the base station;a second acquiring subunit, configured to determine, according to asignaling plane address of an acquired PGW and the failure informationof the signaling plane paths between the SGWs and the PGWs, a signalingplane address of each SGW having a failed signaling plane path to theacquired PGW; a third acquiring subunit, configured to determine,according to a user plane address of an acquired PGW and the failureinformation of the user plane paths between the SGWs and the PGWs, asignaling plane address of each SGW having a failed user plane path tothe acquired PGW.
 13. The device according to claim 11, wherein theselecting module comprises: a first storing unit, configured to receivean S1-AP message sent by the base station after the base station detectsthat a user path to the selected SGW fails, wherein the S1-AP messagecomprises a failure identifier of the user plane path; and storecorrespondence between information of the base station and a signalingplane address of the selected SGW into the failure information of theuser plane paths between the base station and the SGWs; and a firstselecting unit, configured to select, according to the failureinformation of the user plane paths between the base station and theSGWs and the acquired signaling plane address list of SGWs serving theUE, an SGW having no failed path to the base station to serve the UE.14. The device according to claim 11, wherein the selecting modulecomprises: a second storing unit, configured to receive an S11 interfacemessage sent by the selected SGW after the selected SGW detects that auser path to the base station fails, wherein the S11 interface messagecomprises a failure identifier of the user plane path to the basestation; and store correspondence between information of the basestation and a signaling plane address of the selected SGW into thefailure information of the user plane paths between the base station andthe SGWs; and a second selecting unit, configured to select, accordingto the failure information of the user plane paths between the basestation and the SGWs and the acquired signaling plane address list ofSGWs serving the UE, an SGW having no failed path to the base station toserve the UE.
 15. The device according to claim 11, wherein theselecting module comprises: a third storing unit, configured to receivean S11 interface message sent by the selected SGW after the selected SGWdetects that a signaling plane path to an acquired PGW fails, whereinthe S11 interface message comprises a failure identifier of thesignaling plane path to the PGW; and store correspondence between asignaling plane address of the selected SGW and a signaling planeaddress of the acquired PGW into the failure information of thesignaling plane paths between the SGWs and the PGWs; and a thirdselecting unit, configured to select, according to the failureinformation of the signaling plane paths between the PGWs and the SGWsand the acquired signaling plane address list of SGWs serving the UE, anSGW having no failed path to the PGW to serve the UE.
 16. The deviceaccording to claim 11, wherein the selecting module comprises: a fourthstoring unit, configured to receive an S11 interface message sent by theselected SGW after the selected SGW detects that a user plane path to anacquired PGW fails, wherein the S11 interface message comprises afailure identifier of the user plane path to the PGW; and storecorrespondence between a signaling plane address of the selected SGW anda user plane address of the acquired PGW into the failure information ofthe user paths between the SGWs and the PGWs; and a fourth selectingunit, configured to select, according to the failure information of theuser plane paths between the PGWs and the SGWs and the acquiredsignaling plane address list of SGWs serving the UE, an SGW having nofailed path to the PGW to serve the UE.